Application of colloidal suspensions for polishing advanced materials has become an exceedingly critical aspect of final part formation for the glass and microelectronics industries. Silica and alumina colloids are formed through various techniques and typically require expensive precursor materials in order to ensure the highest purity products. Solutions are stabilized with buffer systems to pH and solids loading values that result in optimal surface finish attainment. Particle size distribution can be adjusted to control the final surface finish, as well as the ability to clean residue abrasive particles from workpiece surfaces after processing.
The level of polish currently available is currently good enough for use as a photomask of a substrate. The real issue, however, is removal of defects. Limitations in the application of polishes surfaces for electronic grade applications is the formation of and inability to remove surface defects. Especially critical is surface damage from polish abrasive scratching. Small surface imperfections easily distort light. Small particle size abrasives have a low (long) removal rate. Also, hard, optical quality pads scratch the surface when used with conventional small particle size abrasives.